The present invention relates to apparatus and methods for cardiac ablation and to sensor structures useful in such apparatus and methods.
Contraction or “beating” of the heart is controlled by electrical impulses generated at nodes within the heart and transmitted along conductive pathways extending within the wall of the heart. Certain diseases of the heart known as cardiac arrhythmias involve abnormal generation or conduction of the electrical impulses. One such arrhythmia is atrial fibrillation or “AF.” Certain cardiac arrhythmias can be treated by deliberately damaging the tissue along a path crossing a route of abnormal conduction, either by surgically cutting the tissue or by applying energy or chemicals to the tissue, so as to form scar. The scar blocks the abnormal conduction and thereby reduces or eliminates AF. For example, in treatment of AF, it has been proposed to ablate tissue in a partial or complete loop around a pulmonary vein within the vein itself, within the ostium or opening connecting the vein to the heart, or within the wall of the heart surrounding the ostium. It would be desirable to perform such ablation using a catheter-based device which can be advanced into the heart through the patient's circulatory system. Despite all efforts in the art, however, still further improvement would be desirable.